1. Field of the Invention
This invention relates to a process for the production of pourable and free-flowing granular detergent ingredients which contain an active substance liquid at room temperature and a fine-particle carrier material for that active substance, and to the use of granules produced by this process for the production of solid detergents.
2. Discussion of Related Art
Modern detergents contain a number of ingredients which, besides those essential to the washing process, such as surfactants and builders, generally include other constituents which can come from such different groups of active substances as foam regulators, redeposition inhibitors, soil release agents, bleaching agents, bleach activators and dye transfer inhibitors. Besides this classification of active substances, typical detergent ingredients can also be classified according to their aggregate state at room temperature. Accordingly, a distinction may be drawn between solid and liquid ingredients of detergents. The percentage content of liquid ingredients in solid powder-form detergents should naturally not exceed a certain upper limit because otherwise the individual particles would cake together, the flowability of the detergent and its pourability from the box would no longer be guaranteed and the detergent would become far more difficult to dose and handle by the user. Accordingly, constituents liquid at room temperature are normally incorporated in powder-form detergents in the form of mixtures with solid absorbent carrier materials. Various processes are available for the production of such compounds of solid, powder-form carrier material and liquid active substance. For example, aqueous slurries of carrier material and liquid active substance can be spray-dried. This process is attended by difficulties where substances insoluble in water or not readily dispersible in water are to be processed. In addition, it is limited to substances which have a certain heat resistance and, in addition, has the disadvantage that removal of the water entails relatively high energy consumption. An alternative production process comprises, for example, applying liquids to particles of carrier material moved in a mixer. If the active substances involved are liquid at the temperature of the particulate carrier material, the carrier material to which the liquids are applied is in danger of agglomerating, which leads to a not always desirable increase in the size of the particles, and the particles are in danger of caking on the walls of the mixer. One way of avoiding these dangers is to use a fluidized bed of the carrier material to which the liquid is applied. In this case, however, it is important to bear in mind that a fluidized bed cannot be produced from every substance suitable for use as a solid carrier material and that, in many cases, the particles forming the fluidized bed cannot always be completely prevented from agglomerating.
The problem addressed by the present invention was to provide an alternative production process for granular detergent ingredients containing an active substance at least partly liquid at room temperature and a fine-particle carrier material in which these disadvantages would be avoided.